Japan will upgrade its estimate of North Korea’s nuclear weapons capability in an upcoming annual defence report, saying it seems Pyongyang has already achieved the miniaturisation of warheads, the Yomiuri newspaper said in an unsourced report on Wednesday.

That compares with the assessment in last year’s report in which the government said it was possible North Korea had achieved miniaturisation, the Japanese daily said without citing sources.

The government is planning to approve the report at a cabinet meeting in mid-September. The report will maintain the assessment that North Korea’s military activities pose a “serious and imminent threat”, the Yomiuri said.